Oxa1p, an essential component of the N-tail protein export machinery in mitochondria

AUTOR(ES)

Hell, Kai

FONTE

The National Academy of Sciences

RESUMO

A number of nuclear encoded inner membrane proteins of mitochondria span the membrane in such a manner that their N termini are located in the intermembrane space. Many of these proteins attain this membrane orientation by undergoing an export step from the matrix across the inner membrane. This export process, which resembles bacterial N-tail export from energetic and topogenic signal requirements, is facilitated by Oxa1p, a protein that has homologues throughout prokaryotes and eukaryotes. Oxa1p, as we have previously shown, is required to export the N and C termini of the mitochondrially encoded pCoxII to the intermembrane space. We demonstrate here that imported nuclear encoded proteins physically interact with Oxa1p and depend on Oxa1p for efficient export of their N termini to the intermembrane space. Furthermore, Oxa1p interacts with nascent polypeptide chains synthesized in mitochondria, including the fully synthesized pCoxII and CoxIII species. Thus, Oxa1p represents a component of a general export machinery of the mitochondrial inner membrane.

Documentos Relacionados

• Topogenesis of Mammalian Oxa1, a Component of the Mitochondrial Inner Membrane Protein Export Machinery*S⃞
• YidC, the Escherichia coli homologue of mitochondrial Oxa1p, is a component of the Sec translocase
• A new genetic selection identifies essential residues in SecG, a component of the Escherichia coli protein export machinery.
• The eukaryotic P loop NTPase Nbp35: An essential component of the cytosolic and nuclear iron–sulfur protein assembly machinery
• Azide-resistant mutants of Escherichia coli alter the SecA protein, an azide-sensitive component of the protein export machinery.